A position information aggregation device includes a position information receiving unit receives position information related to the positions of a plurality of mobile communication terminals together with a user ID specifying a user of the terminal corresponding to each position information and an address code of the user, an acquisition rate calculating unit that calculates a position information acquisition rate of each address code of the plurality of terminals using population statistics data and position information of each narrow area in a predetermined broad area, and an aggregating unit that aggregates a population distribution in a certain area by extracting the position information corresponding to the certain area based on the position information received by the position information receiving unit and aggregating the position information in which the position information acquisition rate corresponding to the address code included in the position information is reflected.